PDBsum entry 3qc9

Transferase

PDB id: 3qc9

Contents

Protein chains

486 a.a. *

Ligands

ADP ×4

GOL ×2

Metals

_MG ×8

Waters ×113

* Residue conservation analysis

PDB id:

3qc9

Name:

Transferase

Title:

Crystal structure of cross-linked bovine grk1 t8c/n480c double mutant complexed with adp and mg

Structure:

Rhodopsin kinase. Chain: a, b, c, d. Fragment: unp residues 1-535. Synonym: rk, g protein-coupled receptor kinase 1. Engineered: yes. Mutation: yes

Source:

Bos taurus. Bovine,cow,domestic cattle,domestic cow. Organism_taxid: 9913. Gene: grk1, rhok. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108. Expression_system_cell_line: high 5

Resolution:

2.70Å R-factor: 0.194 R-free: 0.229

Authors:

C.-C.Huang,J.J.G.Tesmer

Key ref:

C.C.Huang et al. (2011). Activation of G protein-coupled receptor kinase 1 involves interactions between its N-terminal region and its kinase domain. Biochemistry, 50, 1940-1949. PubMed id: 21265573

Date:

15-Jan-11 Release date: 16-Feb-11

Protein chains

P28327  (RK_BOVIN) -  Rhodopsin kinase GRK1 from Bos taurus

Seq: 561 a.a.

Struc: 486 a.a.

Enzyme reactions

• Enzyme class: E.C.2.7.11.14 - rhodopsin kinase.
• Reaction:
  1. L-seryl-[rhodopsin] + ATP = O-phospho-L-seryl-[rhodopsin] + ADP + H⁺
  2. L-threonyl-[rhodopsin] + ATP = O-phospho-L-threonyl-[rhodopsin] + ADP + H⁺

L-seryl-[rhodopsin] + ATP = O-phospho-L-seryl-[rhodopsin] (Bound ligand (Het Group name = ADP) corresponds exactly) + ADP + H(+)

L-threonyl-[rhodopsin] + ATP = O-phospho-L-threonyl-[rhodopsin] (Bound ligand (Het Group name = ADP) corresponds exactly) + ADP + H(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Biochemistry 50:1940-1949 (2011)

PubMed id: 21265573

Activation of G protein-coupled receptor kinase 1 involves interactions between its N-terminal region and its kinase domain.

C.C.Huang, T.Orban, B.Jastrzebska, K.Palczewski, J.J.Tesmer.

ABSTRACT

G protein-coupled receptor kinases (GRKs) phosphorylate activated G protein-coupled receptors (GPCRs) to initiate receptor desensitization. In addition to the canonical phosphoacceptor site of the kinase domain, activated receptors bind to a distinct docking site that confers higher affinity and activates GRKs allosterically. Recent mutagenesis and structural studies support a model in which receptor docking activates a GRK by stabilizing the interaction of its ∼20-amino acid N-terminal region with the kinase domain. This interaction in turn stabilizes a closed, more active conformation of the enzyme. To investigate the importance of this interaction for the process of GRK activation, we first validated the functionality of the N-terminal region in rhodopsin kinase (GRK1) by site-directed mutagenesis and then introduced a disulfide bond to cross-link the N-terminal region of GRK1 with its specific binding site on the kinase domain. Characterization of the kinetic and biophysical properties of the cross-linked protein showed that disulfide bond formation greatly enhances the catalytic efficiency of the peptide phosphorylation, but receptor-dependent phosphorylation, Meta II stabilization, and inhibition of transducin activation were unaffected. These data indicate that the interaction of the N-terminal region with the kinase domain is important for GRK activation but does not dictate the affinity of GRKs for activated receptors.